Fluid compressor



. April 24, 1945. A E, ROY

FLUID COMPRESSOR Filed Sept. 19, 1941 2 Sheets-Sheet l MAJ uw@ .U

nnentor; ALBERT E `/Qox va 'if la Gttomeg.

pri 24, 1945. A. E. ROY

FLUID COMPRESSOR Filed Sept. 19, 1941 2 Sheets-Shea? 2 A L 55,27 E. /QO Y,

@Gttorneg.

Patented Apr. 24, 1945 UNITED STATES PATENT TOFFICEl FLUID COMPRESSOR Albert E. Roy, Los Angeles; Calif. Application september 19,l 1941, seria1No.411,542

s claims. (c1. (so-54.6)

My invention relates to a compressor for iuids and which is particularly adapted for use in conjunction with hydraulic mechanism and especially` to that adapted for association vwith hydraulic brake mechanisms and more specically relates to the iluid pressure producing devices moved forward on its compression stroke and toy prevent the pressure in the low pressure cylinder from rising above a desired value.

A further object of my invention is to provide novel mechanism comprising low and high pressure cylinders in communication with each other A during initial movement of .a common iiuid compression element having piston heads mounted thereon, and reciprocal in each of said cylinders, and including novel means for adjusting the maximum value of the pressure built up` in the low pressure cylinder during the brake applying movement of the parts, and to return liquid expelled from said low pressure cylinder into a reservoir after communication with the high pressure cylinder has been cut off from said low pressure cylinder Wfhen the parts move to released position.

' A still further object of my invention is to provide a novel pressure cylinder construction comprising high and low pressure cylinders and novel valve and port means whereby on the commencement of the operative movement of fluid compression pistons in said cylinders, the pressure in the low pressure cylinder during the initial movement of the pistons is quickly transferred to the high pressure cylinder for taking up the slack in the brake mechanism parts, and then pressure is transmitted at a higher value in the high pressure cylinder by further operative movement ofthe pistons, and whereby any subsequent pressure in the low pressure cylinders is relieved during further operation of the fluid compression member:

A still further object is to provide a novel iiuid compressor whereby the uid pressure is controlled by novel valve and by-pass means to obtain proper balance of the fluid pressure during the compression stroke.

compressor whereby a remote mechanism may be instantly operated and high pressures immedi- A ,ately conveyed thereto for subsequent operating purposes v A still further object is to provide a novel, simple vand eicient uid compressor adapted to be connected to pressure distributing lines of hydraulic braking mechanism and whereby a highv line pressure may be maintained in such uid distributing lines.

The invention also resides in the parts and combinations of parts, and in the'particular provision, relative disposition and cooperative functions of the parts as hereinafter more fully described in detail, illustrated in the drawings, and particularlypointed out in the claims.

Other objects, advantages and features of invention may appear from the accompanying drawings, the subjoined detail description, an the appended claims. l

The accompanying drawings illustrate the invention in some of the forms I at present deem ous other applications that will readily occur to persons skilled in the art.

Figure 1 is a vertical sectional View of my preferred form of 'pressure producing construction, and showing the piston in retracted position.

Fig. 2 is a transverse cross sectional view on reduced scale, and taken on line 2-2, Fig. 1, and looking in the direction of the arrows.

Fig. 3 is an enlarged detail plan view ofthe face of the relief valve, taken on line 3-3, Fig. 1, and looking in the direction of the arrows.

Fig. 4 is a vertical sectional View analogous to Fig. l showing a modified embodiment of my invention.

Y Fig..5 is a fragmental axial sectional view show- 1 ing a modied form of the high pressure cylinder piston head and associated valve structure.

In the preferred form of the invention illustrated in Figs. 1-3 of the drawings, it will be seen that I provide a low pressure cylinder A and a high pressure cylinder B of smaller diameter than cylinder A, and arranged co-axially therewith, and pressure` release means generally indicated at C for the low pressure cylinder A, said pressure release means being arranged in a fluid reservoir and also serves to provide communica- A still further object is to provide .a novel fluid a lower arm 3 pivotally connected by pivot bolt 4 to one end of 'a push rod 5, which is rounded at its inner end and engages the recess 5' formed in the back of the reciprocal piston element 6 to force the same inwardly into the cylinders A and B upon depression of the brake pedal I.

An oil or fluid reservoir 1 is provided with an air bleed vent 9 that serves to keep the reservoir in communication with the atmosphere,` and is formed by yaiplurality ofports or openings formed in a plug Iii which is removably mounted in a lilling opening I0 formed in a cover plate 28 to en able uid to be placed in the reservoir 1. To pregvent uid from splashing out .through openings' 9,v a baille in the form of a wad of steel wool 8 is positioned in the reservoir beneath the plug I0'.

The piston element 6 is -prb'vide'dv -with a low` pressure piston head 6a and a high pressure p iston head 6b; a leak proof washer or rubber pis'- ton cup II is secured to piston-head .8d by forcing the same overv ah'ead- I2 and. into a recess I2 formed-.in the piston head. 6a sol as to retain the same thereon and said cup I I operates inthe low pressure cylinder A- to force fluid (preferably oil) therealong, and to inhibit theiseepage ot-fluid fromthe cylinder past the piston.` A spring I4, arrangedwithin cylinder A and' betweenthe inner face of piston head 8a and a wall I3 `that `close the top of reservoir 1.

' Therelief valve C as-shown in Figs. 1-3, comprises a valve stem 21 carrying a valve head 28 yg which seats on a valve seat 29 formed in the lower end of a bushing 30 that is screw threaded at 3l into the lower wall 32v of the reservoir 1.

The valve stem 21 is threaded and iitted with an adjusting nut 34 for a spring 35 arranged betweenV the head of nut 34 and the upper face 36 of an auxiliary plate valve 31, that has a tubular guide 38, slidable on the valve stem 21. The lower face`- of auxiliary valve 31 normally rests upon the ,top shoulder 39 o'f the body of valve head 28.

Auxiliary valve ports 40 are provided through -the body of kvalve head 28 toV permit fluid to ilow therethrough from cylinder A to reservoirl under control of auxiliary valveV 31. The lower faceof valve 31 is provided with a' minuteradlal groove t 56' that communicates with ports 40 either direct forms the inner end of the cylinder A, serves to i return the piston element Band rod' 5 to retracted or inoperative position, aslshov'vn in Fig. 1.

The piston element 6 is' retainedagainst displacement from the open end of cylinder A-by a retaining ring .90 seated in a circumferential groovey inthe wall of the' cylinder;v l

`The high pressure piston Vhead 8b is provided on the inner end of the reducedbodyvpo'iftion of piston element 6 and is provided with a plurality of ports I5 that extend longitudinallythroug'h the piston head 6b and provide for controlled communication between rthe'cylinders AA andB. The piston head 8b is` provided at its inner endV and within the cylinder -B with a floating rubber piston cup or valve I1 which is provided with a! i metalY ring insert I8 thatfoverlies and forms an effective closure for the ports I5` whenth'e'piston cup or floating valve I14is moved against the end SI high pressure piston headl G'brwhichforms a valve seat forthe valve I1. i l y The valve I1 is retained in` limited floating movement relative toL its seat .9i by a stud bolt I9, the stemfof which slidably. supports a metal retaining washer 194, that preferablyis frustroconical and has four prongs IB. thereon so as tot provide spaces 20 throughwhich fluid may freely pass, as hereinaiterexplained.` Studl I9 is screwed into a tapped bore in piston head 617,1 and itwill be noted thata small` clearance is` provided between valve |1 and the stem of stud I9`;fland that a bleed port or passageway52 is. drilled Athrough the head of stud I9 and. into.` the length of the stud stem and communicates with the clearance space "5I between the stud and. valvef I1. The bleed port 52 provides for communication betweenv the interior of the high pressure. cylinder 13` 'and the low pressure cylinder,l A through thespace v5I and ports l5 when the valve I1' i's moved foi-, ward against the washer I9', and valve I1 is provided with a frustro-conical recess 92'inits i'nneri face providinga valve seat for washer I9'.

The cylinder B has ahead in .they forin-` ofa nut 2l threaded thereinto andis provided with a discharge port 22 that is suitably connected to aiiuid pressure delivery pipev 23 which leads tothe remotelylocated nuid actuated motors (not shown) or through a minute circular groove 58 formed in the upper surface or on the top shoulder 39 of Valve head 28', and which groove 58 connects the ports 49; thereby providing a slight bleeding action-v between cylinder A and reservoir 1. As soon aepressure builds 11p/inthe low-pressure cylinder A, the' valve 28 will close, thereafter iluid will be forced upwardly through the ports and against the tension of the spring 35. The tension of the spring 35 will close` the4 auxiliary valve 31, while there isv still some pressure in the cylinder A. It

is this-last bit of` fluid under pressure which bleeds through the groove 58 and thence through the radial groove 56 into the reservoir C.

Pins 42, 42 extending from bushing 30A and valve 31 are provided to limit the rotation of the iioating valve 31 when the screw 34 is adjusted to lvary the tension of Aspring 35 and thus determine the degree of pressure required to operate valves 28 and 31.

The ange 94 rof'bushing 30 is provided on its upper surface within reservoir 1l with a plurality of grooves. 95 that extend radially from the grooves 96 formed in the bore of` bushing 30 and through which the body of valve Ahead 28 reciprocates, thereby providing for free iiow of fluid from reservoir 1 to cylinder -A when the auxiliary valve 31 is closed and until the valve 28 is Aseated upon its seat 29 by compression-of fluid in cylinder Af and upon release of such compression the valve 3-1 will be urged by spring 35 upon the top shouln der 39 and then the valves 31 and 28 may move as a unit by gravity to open valve 28 to permit -i `free iiow of fluid from reservoir to cylinder A.

` `ranged low and high pressure cylinders A and B and reservoir 1 with air bleed vent 9 and steel wool packing 8 for the vent are similar in construction toy that shown in Fig. 1 andcarry the same reference numerals as in that figur but the j L construction of conduits of controlling and' put-A ting the low and high pressure cylinders into combleed port 50 is closed by piston valveuIl. This s initial movement serves to immediately ll the munication with each other and also the valve means C serving to release excess pressure in the low pressure cylinder after communicationA between the cylinders has been interrupted, are of modified construction.

In Fig. 4 the low pressure cylinder A and the high pressure cylinder B are shown connected by a passage 6I formed in a wall of the housing embracing such cylinders, and is controlled by a ball check valve |52 pressed into engagement with seat 63 by a light spring t arranged between the ball and an adjustable abutment screw t5. It will be noted that passage 6| connects beyond the check valve 62 by a branch passage 6 Ia with the interior of the high pressure cylinder B.

The relief valve C in Fig. 4 comprises a valve head 6'! in the form of a circular disc having an upwardly projecting hollow stem 69, and a downwardly and depending skirt Ill of lesser diameter than the disc 61 and concentrically arranged relatively thereto, slidably rits in an aperture in the lower wall 32 of the reservoir I. Slots or apertures 1| are formed in the skirt portion 'I0 just under the lower side of the disc 6l and when the valve 6l is seated on its seat formed by contact with wall 32 the apertures 'lI will be closed.

Ihe disc El is provided 'with apertures I2 adjacent stem 63 and within the area defined by skirt 10, and a smaller disc valve 'I3 is floatingly mounted by a stem I4 nested in the hollow stem B9 of disc valve G1 and underlies the apertures in position to obturate them when fluid forced from cylinder A into the reservoir 'I carries the disc valve I3 upwardly against the underside of the valve head 61.

justment thereof relative to its seat. Pin 98 secured in stem 69 and extending through slot 99 in stem 'I4 prevents rotation of valve 'I3 where adjusting nut 91 is operated and also prevents ac-`vv cidental displacement of valve 13.

A nut Sl threaded on stem Ill retains valve 'I3 in position and provides for ad- The relief valve head 6l normally urged against its seat by a coil spring 68 that operates between head 61 and an abutment I6 that has a threaded stem 'II extending therefrom into a threaded sleeve 1B which extends through the cover plate 26 where a knurled nut 'I5 is secured thereto by a set screw T9. The tension of spring 68 may be varied by rotation of the sleeve 'I8 thus causing up or down movement of the upper abutment 'I6 of the spring. A flange IBB on sleeve I8 engages the underside of cover 26 and cooperates therewith and with nut 'I5 to prevent axial displacement of sleeve I8 and provide for ease of assembly.

It will be noted that the cylinder head for the high compression cylinder B is solid and provided with oil grooves |02, and that the rubber piston cup I G3 is secured to the head IDI by kthe employment of a disk |04 and securing element |05.

Otherwise in the modified structure where the parts are analogous they have been given like reference characters and for the sake of brevity further description thereof is omitted.

In operation of the device shown in Figs. 1-3V and 'assuming the parts are initially in the released or retracted position as shown in Fig. 1, when pedal I is depressed the piston element E through rod 5 starts its compression stroke and uid in low pressure cylinder A is displaced, at once closing valve 28 and moving piston head I1 away from piston 6b and flowing through ports I5, clearance 5| and spaces 20 into cylinder B; if washer I9 momentarily closes the clearance space 5| oil will pass through passage 52, and

fluid pressure deliverypipes and assooiatedfmotors, due to the large compressing area of head Ia and cylinder A, thereby bringing the brake shoes into engagement with the brake drum with a minimum movement of the pedal I. The pressure in cylinder B thereafter becomes high enough to move piston cup |I against piston head 6b, after which excess compressed fluid from the low pressure cylinder A raises plate valve 31 and enters reservoir 1 through ports 40. High pressure cylinder B is then sealed against escape of iiuid through any path except through loutlet pipe 23, and continued depression 0f the pedal I applies the full pressure of fluid compressed in cylinder B to the braking mechanism or the remote iiuid pressure actuated motors. When pedal I is released spring I4 aids in returning the piston element 6 to initial position and suchreturn becomes effective to return the pedal to retracted position and spring mechanism (not shown) of element 6 tends to create a vacuum to open valves I'I and 28 and fluid from reservoir 'I will quickly ll all parts of the cylinders and connecting ports.

In the operation of the device constructed as shown in Fig. 4 the action of the parts is similar except that a bleed passage 52 is not provided, and fluid from low pressure cylinder A flows into the high pressure cylinder B during the initial operation of the device through conduit 6| past check valve 62 which is also opened during return movement of the piston element to refill the cylinder B.

In` Fig. 5 as shown a modified form of valve control means for the high pressure cylinder and in which the piston element is provided with a high pressure cylinder head |20 to which a rubber piston cup |2| is secured by screw |22 threaded into axial bore |23 provided in head |20 and which screw |22 has flared head |24 that extends substantially to the periphery of the cup |2| to maintain the same in position. The screw |22 has an axial bore |25 that communicates with the bore |23` which is extended at its inner end by bore |26 to communicate with the low pressure cylinder. A ball check valve |21 operates to control flow of fluid between the pressure cylinders so as to permit fluid to iiow from thelow pressure to the high pressure cylinder and to prevent reverse ow of fluid therethrough. The ball check valve |21 is normally urged into seated position by a light spring |28 operating betwee ball 2l and the inner end of screw |22.

From the foregoing it will be observed that in the operation of my uid compressor a slight depression of the pedal operates the piston element and such operation completely fllls the iiuid pressure lines and huid operated motors and places the brake shoes into engagement with the brake drums, the low pressure cylinder then cuts off and further depression of the brake pedal operates compressed iiuid in the high pressure cylinder and forces the same through the fluid pressure lines for braking operation. I, therefore, obtain immediate operation of the fluid operated motors by slight pedal pressure and thereafter pedal pressure is available for braking operation, whereas, heretofore considerable pedal operation was required in order to obtain high line pres- I sure or extraneous apparatus was required.

Heretofore, the pressure in fluid distributing lines has been obtained in varying degrees from approximately nine I pounds to one thousand pounds, and I have found from tests' madei with my device that' the pressure'in the. uidpressure distributing lines is materially increased so that fluid pressures have-'been obtained in varying degrees from approximately nine pounds tof two thousand pounds.

I have also found that the. auxiliary valve 36 may be rigidly associated with thee top shoulder 39, and in that eventthe grooves t and 58 provide sucient' passage from the low pressure cylinder. to the oil reservoir to relieve-excess pressureth'at may be createdtherein.

I claim:

1. A fluid compressor: comprising:4v auid: reservoir; a low'pressure cylinder supplied therefrom; a high pressure cylinder coaxial with said low pressure cylinder; a4 common piston element forv said cylinders` provided with a piston head working in the low pressure'cylinder'and a piston head working. inthe high` pressure cylinder, there being a passageway in said latter head. connecting said cylinders; a retaining stud extending. from the forward end of said high pressure head; a. floating valve loosely held on. said stud for limited axial movement thereon and providing an axial annular passage around said stud communicatingV withv said head passage when said valve is away from said` head,'said valve being adapted'to close said head passage. when seated against said head; and a washer carried on said.

stud` forward of' said valve provided with an; aperture communicating with said annular passageway when said valve is seated on said. head, and adapted to close the same when said valve isl at the other end of its stroke away from. said head; whereby fluid passes from the low pressure cylinder tothe high pressure cylinder during initial operation of thevpiston element on its compression stroke, and is prevented from returning during completion of said stroke.

2. A fluid compressor comprising:

from; a high pressure cylinder. coaxial with` said low pressure cylinder;;a common piston element for said cylinders provided with a piston head;

working in the low pressure cylinder and a pist0n head working in the high pressure cylinder, there being a plurality of longitudinal passageways in said latter head' connecting said cylinders; a retaining stud extending from. the for-V ward end of said high pressure head; a floating valve loosely held: on saidV stud for limited axial movement thereon Tand-providing an axial annular passage around said stud communicating with said head passages when said'valveis away from said head, said valve being provided with an annular insert fast to its rear faceA and adapted to close said head passagesl when seated against said head; and a washer carried. on said stud forward of said valve provided with. an aperture communicating 'with said: annular passageway when said valveV is seated onsaid head, and adaptedV to close the samer when said valve is at the other end'of its stroke away from said head; whereby fluid rpasses from thel low` pressure cyl-Vv inder to the high pressure cylinder during initial operation of the piston element on its compressionstroke, and is prevented from returning durin'g completion of said stroke.l

3.'A yfluid compressor comprising: a fluid res--` ervoir; a low pressure cylinderv supplied therefrom; a' high pressure cylinder coaxial with` said low pressure cylinder; aA `common piston 'element for' saidy cylinders provided.l withv a .piston head working in the` lowpressurei'cylinder and a1 pisa fluid reservoir; a low pressure cylinder supplied thereaetnanet ton head working in the high pressure'cylinder, there being a passageway' in-said latter head4 connecting said cylinders; a retaining stud extending from the forward end of said: high pressure head; a floating valve loosely held on said stud for limited axial movement thereon andproviding an axial annular passage around said stud communicating with said head passage when said valve is away from said head, said valve being adapted to close said head passage when seated against said head; an axial bleed passage in said` stud connecting said annular passage with the high pressure cylinder irrespective of the position of said valve on said stud; and a washer carried on said stud forward of said valve provided with an aperture communicating with said annular passageway when said valve is seated on said head, and adapted to close the samewhen,

said valve is at the other end of its stroke away fromsaid head; whereby fluid passes from the llow pressure cylinder to the high pressure cylinder during initial operation of the piston ele- 'ment on` its compression stroke, and is prevented from returning'during completion of said stroke.

4. A fluid compressor comprising: a fluid reservoir; a low pressure cylinder supplied therefrom; a high pressure cylinder coaxial with said low pressure cylinder; a common piston element for said cylinders provided with a piston head working inV the low pressure cylinder and a pistonhead workin-g in the high pressure cylinder, there beinga plurality of longitudinal passageways in said latter head 'connecting said cylinders; a retaining stud extending from the forward end of said high pressure head; a floating valveV loosely held on said stud for limtedaxial movementy thereon and providing an axial annular passage around said stud communicating with said head passages whenr said valve is away from said head, said valve being provided with an annular insert fast to its rear face and adapted to close said head passages when seated against said head; an axial bleed passage in said stud connecting said annular passage with` the high pressure cylinder irrespective of the position of said valve on said stud.; and a washer carried `on said stud forward 0f said Valve provided with an aperture communicating with said annular passageway when said valve is seated on said head, and adapted to close the same when said valve is` at the other end of its stroke away from said head; whereby iluid passes from the low pressure cylinder to the high pressure cylinder during initial operation ofthe piston element on its compression stroke, and is prevented from returning during completion of said stroke.y

5. A fluidv compressor comprising: a fluid reservoir; a low pressure cylinder supplied therefrom; ahigh pressure cylinder coaxial with said low pressure cylinder; a common piston element for said cylinders provided with a piston head working in the low pressure cylinder and a piston head working in the high pressure cylinder, there being a passageway in said latter head connecting said cylinders; a retaining stud extending from the forward end of said high pressure head: a floating valve loosely held on said stud for limited axial movement thereon and providing an said valve on said stud; whereby fluid passes from the low pressure cylinder to the high pressure cylinder during initial operation of the piston element on its compression stroke, and is prevented from returning during completion of said stroke.

6. A fluid compressor comprising: a fluid reservoir; a low pressure cylinder supplied therefrom; a high pressure cylinder coaxial with said low pressure cylinder; a common piston element for said cylinders provided with a piston headworking in the low pressure cylinder and a piston head working in the high pressure cylinder, there being a plurality of longitudinal passageways in said latter head connecting said cylinders; a retaining stud extending from the forward end of said high pressure head; a iioating valve loosely held on said Stud for limited axial movement thereon and providing an axial annular passage around said stud communicating with said head passages when said valve is away from said head, said valve 'being provided with an annular insert fast to its rear face and adapted to close said head passages when seated against said head; and an axial bleed passage in said stud connecting said annular passage with the high pressure cylinder irrespective of the position of said valve on said stud; whereby iiuid passes from the low pressure cylinder to the high pressure cylinder during initial roperation of the piston element on its compression stroke, and is prevented from returning during completion of said stroke.

7. A fluid compressor comprising a iiuid reservoir; a low pressure cylinder supplied therefrom; a high pressure cylinder coaxial with said low pressure cylinder; a common piston element for said cylinders provided with a piston head working in the low pressure cylinder and a piston head working in the high pressure cylinder, there being a passageway in said latter head connecting said cylinders; a retaining stud extending from the forward end of said high pressurehead; a

iioating valve loosely held on said stud for limited axial movement thereon and providing a passage communicating with said head passage v when said valve is away from said head, said valve being adapted to close said head passage when seated against said head; and a washer carried on said stud forward of said valve provided with an aperture communicating with said valve passageway when said valve is seated on said head, and adapted to close the Same when said valve is at the other end of its stroke away from said head; whereby uid passes from the low pressure cylinder to the high pressure cylinder during initial operation of the piston ele-- ment on its compression stroke, and is prevented from returning during completion of said stroke.

8. A fluid compressor comprising: a fluid reservoir; a low pressure cylinder supplied therefrom; a high pressure cylinder coaxial with said low pressure cylinder; a, common piston element for said cylinders provided with a piston head working in the low pressure cylinder and a piston head working in the high pressure cylinder, there being a passageway in said latter head connecting said cylinders; a iioating valve loosely held on the forward end of said high pressure piston head for limited axial movement with respect thereto and providing a passage communi-- eating with said head passage when said valve is away from said head, said valve being adapted to' ALBERT E. ROY. 

